This invention relates to poly(arylene sulfide) and, more particularly, to compositions of arylene sulfide polymer and filler materials. In another of its aspects this invention relates to arylene sulfide polymer compositions having good insulation resistance. In yet another aspect of this invention it relates to arylene sulfide polymer compositions having good surface gloss. In yet another aspect of the invention it relates to the addition of calcium sulfate to polymeric compositions.
One of the important uses of poly(arylene sulfide) is in molding compositions. By combining poly(arylene sulfide) with reinforcing agents such as fiberglass and with fillers, molding compositions can be tailored for certain end uses. Up until now a composition in which poly(arylene sulfide), fiberglass, and calcium carbonate are combined has been a standard for providing molding compositions having good strength, good insulation resistance, and good surface gloss. It has now been found that by substituting calcium sulfate for the calcium carbonate in these compositions that compounds that upon molding have better surface gloss and insulation resistance than those containing calcium carbonate and having equally good strength characteristics can be produced. It has also been found that by restricting the particle size of the calcium sulfate incorporated in the compositions to a finely ground material that the surface gloss and insulation resistance of the molded products can be further improved. Articles such as automotive headlamp reflectors and the like molded from the invention compositions exhibit a good balance of mechanical properties and smooth surfaces.
It is therefore an object of this invention to provide molding compositions based on poly(arylene sulfide) that have good insulation resistance and surface gloss when molded. It is another object of this invention to provide a filled polymer composition in which calcium sulfate is used as filler. It is still another object of this invention to provide a method for improving surface gloss and insulation resistance characteristics of molded objects produced from poly(arylene sulfide).
Other aspects, objects and the various advantages of this invention will become apparent upon reading this specification and the appended claims.